Fuel injection pumps for I.C. engines

ABSTRACT

A fuel injection pump for supplying fuel to an internal combustion engine includes a pair of pumping plungers which are actuated by cam lobes formed on the internal periphery of an annular cam ring. Roller carrying shoes are interposed between the plungers and the cam lobes and are axially movable. A stop is provided to limit the outward movement of the shoes and the stop and shoes are provided with complementary inclined contacting surfaces whereby the extent of outward movement of the plungers depends upon the axial positions of the roller shoes.

United States Patent 1191 1111 3,910,723

Bonin Oct. 7, 1975 [54] FUEL INJECTION PUMPS FOR C, 3,650,259 3/1972 Garnie 417/462 X ENGINES 3,847,509 11 1974 Bonin 417/214 Inventor: Jean Claude Bonin, Blois, France Assignee: Roto Diesel, Clichy, France Filed: Mar. 12, 1974 Appl. No.: 450,431

Foreign Application Priority Data Mar. 14, 1973 France 73.09050 US. Cl 417/214; 417/462 Int. Cl. F04B 19/02; F04B 29/00;

F04B 49/00 Field of Search 417/214, 462

References Cited UNITED STATES PATENTS 4/1958 Roosa 417/462 X 9/1961 Volossevich 417/462 X 8/1967 Davis 417/214 X Primary Examiner-William L. Freeh Assistant Examiner-Richard E. Gluck Attorney, Agent, or FirmFinnegan, Henderson, Farahow & Garrett [57] ABSTRACT 8 Claims, 8 Drawing Figures I ///(/////////////fl lljllllllllllllllljlll US. Patent 0a. 7,1975 Sheet 3 of 3 3,910,723

FUEL INJECTION PUIVIPS FOR LC. ENGINES This invention relates to fuel injection pumps of the kind described in the specification of Patent Application Ser. No. 316,485 filed Dec. 19, 1972, now US. Pat. No. 3,847,509.

In the application referred to above there is described a fuel injection pump for supplying fuel to internal combustion engines comprises a body part, a distributor member rotatable within the body part and adapted to be driven in timed relationship with an engine with which the pump is associated, a transverse bore formed in the distributor member, a pair of pumping plungers reciprocably mounted within the bore, a pair of shoes slidable in radial slots at the outeis ends of said bore, the shoes engaging the plungers during inward movement of the shoes, cam engaging means carried by said shoes, an annular cam ring surrounding said distributor, cam lobes formed on the internal periphery of said cam ring and engaging with said cam engaging means during rotation of said distributor member to impart inward movement to said shoes and plungers, fuel delivery means for conveying fuel displaced from said bore to a plurality of fuel outlets in turn, fuel inlet means for supplying fuel to said bore during the periods when the plungers can move outwardly, and means for moving the shoes axially whereby the amount of fuel which can be supplied through the fuel outlets can be varied.

According to a further feature of the invention said shoes are provided with an inclined zone and the distributor member mounts an abutment engageable with the inclined zone to limit the outward movement of the shoes.

Examples of injection pumps in accordance with the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a sectional side elevation of part of one example,

FIGS. 2 and 3 are part sections on the lines IIII and IlllIl of FIG. 1,

FIG. 4 is a sectional side elevation of part of another example,

FIG. 5 is a part section on the line V-V of FIG. 4, 5,

FIG. 5A is a view in the direction of the arrow A of FIG. 5.

FIG. 6 is a sectional side elevation of part of a further example, and

FIG. 7 is a graph showing of fuel delivery for the pump shown in FIG. 6.

With reference to FIGS. 1, 2 and 3 of the drawings there is provided a pump body 10 defining a cylindrical cavity in which is mounted a fixed sleeve 11. Mounted within the sleeve 11 is a rotary distributor member 12 which is adapted to be driven in timed relationship with an associated engine by means of a drive shaft 13. Moreover, formed within the distributor member is a transversely extending bore 14 in which is mounted a pair of pumping plungers 15. The bore communicates with a passage 16 which in known manner communicates with fuel outlets 17 in turn, formed in the body.

Surrounding the distributor member 12 is an annular carrier 18. The carrier is axially movable on the distributor member 12 but is angularly movable therewith. The carrier is provided with a pair of radial slots in which are mounted shoes 19 which carry rollers 20. Surrounding the carrier 18 is an annular cam ring 21 on the internal peripheral surface of which as seen in FIG. 2, are formed a plurality of cam lobes 22. The cam lobes 22 in use, are engaged by the rollers 20 to effect inward movement of the plungers 15 during the time when the passage 16 is in communication with a fuel outlet 17. Outward movement of the plungers is under the action of fuel which is supplied to the transverse bore 14 from a source of fuel under pressure.

As will be seen from FIG. 1 the cam lobes 22 are flared or tapered and the effect of this taper is that the inward movement of the plungers and therefore the amount of fuel supplied through the fuel outlet depends upon the axial setting of the annular carrier 18. In the particular arrangement as the carrier is moved towards the right as seen in FIG. 1 the amount of fuel supplied will decrease. At the section line indicated by FIG. 3 the cam lobes have tapered completely and therefore there will be no delivery of fuel.

The axial setting of the carrier 18 is controlled by an axially movable sleeve 23 slidable on the shaft 13. The sleeve 23 is provided with a first flange 24 against which bears the forked end of a lever 25. The lever 25 is pivotally mounted about a fulcrum point 26 and the other end of the lever is connected to a coiled tension spring 27 the force exerted by which can be adjusted by a manually operable device. The sleeve 23 is provided with a further flange 28 which is acted upon by the toe portions of centrifugal weights 29. The weights 29 are mounted in a cage 30 driven by the drive shaft 13. The arrangement is such that for a given setting of the manually operable device as the speed of the engine increases the sleeve 23 will move towards the right as seen in FIG. 1 and like movement will be imparted to the annular carrier 18 thereby reducing the amount of fuel supplied to the engine. In the event that the force exerted by the spring 27 is increased or the engine speed decreases, the sleeve 23 will move towards the left and the annular carrier 18 is maintained in contact with the sleeve 23 by means of the force exerted by the spring loading of rams 31 carried within the sleeve 11. It will be appreciated that the springs loading the rams 31 assist the action of the spring 27.

In the arrangement shown in FIGS. 4 and 5A the apparatus includes a pump body 10 and sleeve 11 in which is mounted the distributor member 12. The distributor member as in the previous example, is provided with the transverse bore 14 accommodating plungers 15, the bore communicating with passage 16, the latter being positioned to register in turn with fuel outlets 17. The carrier member 18 is again provided on the distributor member and at one end is acted upon by a spring 32.

. The carrier member 18 is provided with a pair of radial slots in which are mounted shoes 33 respectively each mounting a roller 34. The rollers 34 co-operate with cam lobes formed on the internal periphery of an annular cam ring 35 in this case the cam lobes being of constant height throughout their axial length. Moreover, as seen in FIG. 5 a leaf spring stop 36 is provided and this is mounted on the rotor 12 and has its ends turned inwardly so as to be engageable by the roller shoes 33. Furthermore, as best seen in FIG. 5A, the thickness of each end of the stop 36 varies throughout their axial length and in a manner complementary to the shape of the presented edges of the side portions of the roller shoes 33. In this manner the maximum amount of fuel which can be supplied to the engine depends upon the axial setting of the carrier member 18. In the arrangement shown as the carrier member moves towards the left, as seen in FIG. 4, the amount of fuel which can be supplied increases.

The carrier is moved by fuel pressure actuated rams 37 only one of which is shown. As shown these have small extensions which pass through apertures in a stop plate 38 into engagement with the carrier member 18. The main portion of the rams however can engage the stop plate 38 to move same into contact with an annular stop member 39. At one point the stop member 39 is provided with a slot having a tapered end wall with which engages the complementarily tapered end of a manually adjustable member 40. The arrangement is such that the axial setting of the carrier member 18 is determined by the fuel pressure which is applied to the rams 37. As the fuel pressure is increased then the carrier member is moved to the left against the action of the spring 32. As a result of such movement, the amount of fuel which can be supplied is increased. The maximum amount of fuel which can be supplied occurs when the main portions of the rams 37 engage the stop plate 38 and move the latter into engagement with the stop member 39. When this abutment takes place, any further increase in fuel pressure will not bring about any further increase in the maximum amount of fuel which can be supplied. The actual quantity of fuel supplied by the apparatus is controlled in a well-known manner, such as by means of a throttle. It will be appreciated that the direction of thickness variation of the end portions of the leaf stop 36 and the inclination of the edges of the shoes may be in the opposite direction to that which is shown. In this case movement of the carrier towards the left will effect a decrease in the amount of fuel supplied. With this arrangement the pump can supply extra fuel for starting purposes and this will decrease as the pressure applied to the rams increases. The annular stop member 39 again acts as a maximum fuel stop since it determines how far the carrier 18 can be moved by the rams 37 in the direction to reduce the maximum fuel supplied to the engine.

Turning now to the arrangement shown in FIG. 6, parts similar to those of FIG. 4 are given the same reference numerals. In this arrangement the bore 14 together with the plungers are provided but in addition a further transverse bore 41 is provided which accommodates a pair of plungers 42. A carrier member 43 is provided in this case modified to provide location for the shoes 33 and further shoes 44 associated with the plungers 42. The bores 14 and 41 communicate with passages formed in the distributor member which may communicate with a single passage such as the passage 16 shown in the earlier examples or may communicate separate passages feeding fuel to two separate series of fuel outlets.

The shoes 33 are formed as in FIG. 4 and the shoes 44 are formed with a stepped edge indicated at 45. Moreover, the inturned ends of the leaf stop similar to leaf stop 36 shown in FIG. 4 associated with the shoes 44 are formed in a complementary manner. The effect of the shaping of the ends of the leaf stop is better understood with reference to FIG. 7. The vertical axis represents the quantity of fuel pumped and the horizontal axis represents the axial position of the carrier member 43. The lower characteristic represents the output from the bore 14 whilst the upper characteristic represents the output from the bore 41. When the carrier member is in position B the projections on the ends of the leaf stop can enter into the recesses defined in the stepped edge 45. If the carrier member is moved towards position A a point is reached at which the projections can no longer enter into the recesses. As a result the output from the bore 41 is suddenly reduced. The axial setting of the carrier member 43 may be adjusted as with the example described with reference to FIG. 4.

I claim:

1. A fuel injection pump of the kind intended for supplying fuel to internal combustion engines and comprising a body part, a distributor member rotatable within the body part and adapted to be driven in timed relationship with an associated engine, a transverse bore in the distributor member, a pair of pumping plungers reciprocably mounted within the bore, a pair of shoes slidable in radial slots at the outer ends of said bore, said shoes engaging the plungers during inward movement of the shoes, cam engaging means carried by said shoes, an annular cam ring surrounding said distributor, cam lobes formed on the internal periphery of said cam ring and engaging with said cam engaging means during rotation of the distributor member to impart inward movement to said shoes and plungers, fuel delivery means for conveying fuel displaced from said bore to a plurality of fuel outlets in turn, fuel inlet means for supplying fuel to said bore during the periods when the plungers can move outwardly, a carrier member axially slidable on the distributor member, slots in the carrier member in which are located said shoes, respectively, whereby axial movement of the carrier member will effect axial movement of said shoes, inclined surfaces on said shoes, a stop member carried by the distributor member, said stop member defining abutment surfaces engageable with the inclined surfaces on said shoes to limit the outward movement of the shoes whereby axial movement of the carrier member will vary the extent of outward movement of the plungers.

2. A pump as claimed in claim 1, including an element responsive to a fluid pressure for adjusting the axial setting of said carrier member.

3. A pump as claimed in claim 2, in which said element comprises a fluid pressure operable ram, the pump including resilient means for opposing movement of the carrier member by said ram.

4. A pump as claimed in claim 3, including a manually adjustable stop means for limiting the extent of movement of the carrier member by said ram.

5. A pump as claimed in claim 4, in which said stop means comprises an annular stop member surrounding the distributor member, and a manually operable adjustor for determining the axial position of said stop means.

6. A pump as claimed in claim 5, including a stop plate engageable with said annular stop member, an aperture in said stop plate, an extension on said ram of smaller size than the main portion of the ram, said extension passing through said aperture to engage said carrier to impart axial movement thereto as fluid pressure is applied to said ram, said main portion of the ram engaging said stop plate to limit the movement of the ram and thereby the carrier.

7. A pump as claimed in claim 3, including a further bore in the distributor member, a further pair of plungers in said further bore, a further pair of shoes axially movable by said carrier member, said further shoes defining further surfaces engageable by said stop memwhich can enter depending on the axial position of the her. carrier member, projections defined on said stop mem- 8. A pump as claimed in claim 7, in which said furber. ther surfaces are of stepped form defining recesses into 

1. A fuel injection pump of the kind intended for supplying fuel to internal combustion engines and comPrising a body part, a distributor member rotatable within the body part and adapted to be driven in timed relationship with an associated engine, a transverse bore in the distributor member, a pair of pumping plungers reciprocably mounted within the bore, a pair of shoes slidable in radial slots at the outer ends of said bore, said shoes engaging the plungers during inward movement of the shoes, cam engaging means carried by said shoes, an annular cam ring surrounding said distributor, cam lobes formed on the internal periphery of said cam ring and engaging with said cam engaging means during rotation of the distributor member to impart inward movement to said shoes and plungers, fuel delivery means for conveying fuel displaced from said bore to a plurality of fuel outlets in turn, fuel inlet means for supplying fuel to said bore during the periods when the plungers can move outwardly, a carrier member axially slidable on the distributor member, slots in the carrier member in which are located said shoes, respectively, whereby axial movement of the carrier member will effect axial movement of said shoes, inclined surfaces on said shoes, a stop member carried by the distributor member, said stop member defining abutment surfaces engageable with the inclined surfaces on said shoes to limit the outward movement of the shoes whereby axial movement of the carrier member will vary the extent of outward movement of the plungers.
 2. A pump as claimed in claim 1, including an element responsive to a fluid pressure for adjusting the axial setting of said carrier member.
 3. A pump as claimed in claim 2, in which said element comprises a fluid pressure operable ram, the pump including resilient means for opposing movement of the carrier member by said ram.
 4. A pump as claimed in claim 3, including a manually adjustable stop means for limiting the extent of movement of the carrier member by said ram.
 5. A pump as claimed in claim 4, in which said stop means comprises an annular stop member surrounding the distributor member, and a manually operable adjustor for determining the axial position of said stop means.
 6. A pump as claimed in claim 5, including a stop plate engageable with said annular stop member, an aperture in said stop plate, an extension on said ram of smaller size than the main portion of the ram, said extension passing through said aperture to engage said carrier to impart axial movement thereto as fluid pressure is applied to said ram, said main portion of the ram engaging said stop plate to limit the movement of the ram and thereby the carrier.
 7. A pump as claimed in claim 3, including a further bore in the distributor member, a further pair of plungers in said further bore, a further pair of shoes axially movable by said carrier member, said further shoes defining further surfaces engageable by said stop member.
 8. A pump as claimed in claim 7, in which said further surfaces are of stepped form defining recesses into which can enter depending on the axial position of the carrier member, projections defined on said stop member. 